Abstract
Halcrow Group Ltd has been appointed by the South West of England Regional Development Agency (SWRDA) acting on behalf of RWE Npower Renewables Limited, to undertake a metocean field campaign in support of the proposed Wave Hub development. This report serves to summarise field activities and data acquired to date.
A Nortek Acoustic Waves and Current (AWAC) instrument was deployed in the study area to record directional wave and current information. The instrument was placed at a depth of approx 60m off the Cornish coastline (Hayle), UK.
The aim is to collect 18 months of data, which will require a service visit approximately every 3 months. To date there have been four completed deployments, due to an instrument malfunction no data was recorded during the second deployment. This interim report summarises the data collected during the fourth deployment, which covers the period between 10 August 2009 and 27 January 2010.
This fourth deployment was longer than intended, due to stormy conditions during December 2009 and January 2010. During the fourth deployment the instrument functioned as planned and recorded for the entirety of the deployment period. In summary, current flows are tidally dominated with oscillation of flow between the northeast and southeast. Current flows often exceed 0.8 m/s during spring tide events, with a maximum flow of 1.19 m/s recorded on 22 August 2009. Wave heights and period show a high degree of variance over the deployment period. The predominant wave direction is from the west, influenced by Atlantic storm systems. The largest waves recorded exceeded 10m (Hmax) on 4 November 2009. Mean significant wave height (Hm0) for the fourth deployment was 2.20 m. Peak wave periods (Tp) of over 12 seconds are common during periods of larger wave events. Mean wave period (Tm02) was 5.59 seconds.